The present invention relates to a device for compression screwing fractures of the femural neck, consisting of a plate of a sleeve, the sleeve being hollow and cylindrical in shape, the plate of the sleeve being attached by screws to the femur shaft and of a bone screw being located within the sleeve which is provided with a female thread on its head side into which a compression screw having a respective male thread fits.
In the case of fractures of the femural neck, osteosynthesis is gradually taking over from bone replacement with endoprostheses. This shift has led to the development of numerous new operation methods and new instruments.
The screwing and/or nailing together of bone fragments in particular, is used widely and has shown that a pressural force which causes the fracture surfaces to notch or wedge into each other greatly improves the healing of the fracture. In particular, the revascularization of the top fragment is greatly improved due to the better stability and the prevention of destructive shear and rotational movement in such a mechanically endangered area. It is known to construct the inner side of the sleeve of such a compression screw in a step-like fashion so that the head of the compression screw is supported by the ring-shaped face-end of the milled opening. As the screwing length of the bone screw depends on the type and position of the fracture it can vary greatly and the length of the compression screw must be adapted to the actual conditions every time when using a fixed support surface.
This has the disadvantage that if a too short or a too long compression screw is selected it has to be screwed back out again in order to replace it with a screw of the right length. The patient is thus additionally subjected to unnecessary strain.